A phrase meant to be used as a comparison for anything, with or without regard to the image itself. The phrase can be used in a comparison that makes sense to the literal meaning of the image--that is, there is a person named Clancy who has nuts (though "nuts" in itself can be interpreted as many things)--or in an abstraction.

It was raining harder than Clancy's nuts; The sky opened up like Clancy's nuts; I gotta pain that aches like Clancy's nuts; The man was as bald as Clancy's nuts; The woman had more shoes than Clancy's nuts; et al.